A case of endobronchial metastasis of colon cancer mimics sarcoidosis, and a review of related literature.

PURPOSE: Endobronchial metastases (EBM) are defined as bronchoscopically visible lesions histopathologically identical to extrapulmonary tumors. We summarized the literature on endobronchial metastasis of colorectal cancer and give a brief review. METHOD: We present a rare case with an episode mistaken for sarcoidosis and unexpectedly identified as colon cancer by bronchoscopic biopsy. A 53-year-old man with dry cough and dyspnea had diffuse micro lung nodules and lymphadenopathy on CT and PET/CT. He was diagnosed with sarcoidosis and took steroid therapy, but the symptoms could not be alleviated. Bronchoscopy was suggested. He was finally identified with colon cancer by bronchoscopic biopsy, which was confirmed by endoscopic biopsy. We summarise the clinical manifestations, imaging, prognosis of EMB of colorectal cancer. RESULT: EBM are rare. Colorectal cancer is common in EBM and the frequency is increasing. CONCLUSION: EBM should be distinguished from primary lung cancer, sarcoidosis.

Comparison of 18 F-FDG PET/CT and 68 Ga-DOTATATE PET/CT in the Targeted Imaging of Culprit Tumors Causing Osteomalacia.

OBJECTIVE: To assess and compare the performance of fluorine-18-labeled fluorodeoxyglucose positron emission tomography (18 F-FDG-PET/ CT) and gallium-68-labeled tetraazacyclododecanetetraacetic acid-DPhe1-Tyr3-octreotate (68 Ga- DOTATATE) PET/CT in the targeted imaging of culprit tumors causing osteomalacia. METHODS: This was a clinical retrospective analysis. We analyzed 13 patients (five men, eight women; mean age, 49 years; range, 19-55 years) with suspicion of tumor-induced osteomalacia (TIO) between March 2017 and October 2019. All patients underwent two functional imaging methods to locate the culprittumors. Studies were performed on a PET/CT scanner. The injection doses of 18 F- FDG and 68 Ga-DOTATATE were 0.5mCi/kg and approximately 5.0mCi, respectively. In the two scans, the whole body was captured from head to toe 45 to 60 min after intravenous tracer injection. 68 Ga-DOTATATE PET/CT and 18 F-FDG PET/CT imaging results locate culprit tumors according to the following criteria: (i) abnormal foci uptake concentration was observed locally, and the uptake level was higher than the background level of the right lobe of the liver; (ii) combined CT showed or did not have obvious abnormal density changes; and (iii) non-specific ingestion lesions due to fracture, arthritis, necrosis of femoral head are excluded. Compared with the results of pathological examination and clinical follow-up, the sensitivity, specificity and accuracy of 68 Ga-DOTATATE PET/CT imaging and 18 F-FDG PET/CT imaging for TIO were analyzed. RESULTS: All patients had symptoms of osteomalacia and hypophosphatemia. The lag time (symptoms to PET diagnosis) ranged from 2 to 12 years. There were eight cases of TIO patients and five cases of non-TIO patients confirmed by surgery, pathology and follow-up. Among the eight TIO patients, there were six cases (75.0%) of PMTs, one case (12.5%) of giant cell tumor, one case (12.5%) of hemangiopericutoma. Most (n = 6, 75.0%) of the confirmed tumors in our patient population were in the lower extremities, followed by craniofacial regions (n = 1, 12.5%), and torso (n = 1, 12.5%), respectively. Among the five non-TIO patients, there were two cases of Fanconi syndrome, one case of rickets, and two cases of sporadic osteomalacia hypophosphorus. The culprit tumors could be located either in the bone (n = 5, 62.5%) or the soft tissue (n = 3, 37.5%). 18 F-FDG PET/CT was able to localize the tumor in six (6/13, 46.1%) patients. 68 Ga-DOTATATE PET/CT detected tumor in 8 (83.3%) of 13 patients. The sensitivity of 68 Ga-DOTATATE PET/CT imaging and 18 F-FDG PET/CT imaging in the evaluation of TIO in our patient population were 100% (8/8) vs 75% (6/8). The specificity of the two different methods was 80% (4/5). The overall accuracy was 92.3% (12/13) vs 76.9% (10/13). CONCLUSIONS: 68 Ga-DOTATATE PET/CT is very effective in assessing hypophosphatemia patients with TIO typical symptoms compared with 18 F-FDG. Therefore, in clinically suspected cases of hypophosphatemic osteomalacia, 68 Ga-DOTATATE PET/CT should be preferred as an imaging modality investigation to avoid delay in the treatment of this disease.

[Characteristics of extrapulmonary tuberculosis in (18)F-2-fluoro-2-deoxy-D-glucose positron emission tomography-computed tomography: experience from 39 cases].

OBJECTIVE: The clinical manifestations and the imaging features in (18)F-2-fluoro-2-deoxy-D-glucose positron emission tomography ((18)F-FDG PET) of extrapulmonary tuberculosis were not specific and therefore it was difficult to be differentiated from malignancy. This paper tried to analyze the clinical characteristics and findings by (18)F-FDG PET-CT in extrapulmonary tuberculosis, in order to improve the diagnosis of this disease. METHODS: Thirty-nine patients with extrapulmonary tuberculosis underwent (18)F-FDG PET-CT imaging from 2003 - 2011. The diagnosis was confirmed by histopathological examination in all the cases. There were 11 males and 28 females, aging 20 - 67 (60 ± 18) years. A past history of tuberculosis was collected in 5 cases. The PET images were reviewed visually and scored semi-quantitatively with standardized uptake value. The lesions were judged by PET imaging features in conjunction with CT slices and the fused images. RESULTS: Fever was present in 13 cases, and night sweating, weakness and malaise in 17 cases. Pleural effusion was found in 7 cases. Abdominal distention and masses were found in 6 cases, while neck mass was present in 2 cases. Laboratory tests showed that hypoalbuminemia, sedimentation rate increase and positive tuberculin tests were present in 15 cases. CA125 was increased in 3 cases. In PET-CT, lymph node tuberculosis manifested as single or multiple enlarged lymph nodes coalesced and calcified with significant FDG uptake, but ring-like FDG-avidity was also found in some of the lymph nodes. Pleural or peritoneal tuberculosis showed heterogeneous or nodular thickening and in a radio-tracer distribution. Bone tuberculosis manifested as osteolytic osseous destruction and paravertebral cold abscess, while focal radio-agent ring-like intense uptake was present in half the cases. In patients with intestinal tuberculosis, ileocecal circumferential or eccentric thickening was observed, with focal or diffuse high FDG activity. Tuberculosis in adrenal gland, liver, and oviducts all showed lesions with high FDG uptake. CONCLUSIONS: (18)F-FDG PET-CT was helpful for the differential diagnosis of extrapulmonary tuberculosis from malignancy. Osseous and lymph node tuberculosis showed ring-like FDG uptake, which maybe of diagnostic value.

[Value of 18F-FDG and 11C-MET PET-CT in differentiation of brain ringlike-enhanced neoplastic and non-neoplastic lesions on MRI imaging].

OBJECTIVE: To evaluate the value of (18)F-FDG and (11)C-MET PET-CT scan in differentiation of brain ringlike-enhanced lesions on MRI imaging. METHODS: Forty-one brain ringlike-enhanced lesions on MRI imaging including 30 brain tumors and 11 non-neoplastic lesions confirmed pathologically or clinically underwent (18)F-FDG and (11)C-MET PET-CT brain scan. Among them, 15 patients who were suspected to have brain metastasis received body scan by (18)F-FDG PET-CT. Both images were analyzed visually and semi-quantitatively. RESULTS: Visual analysis: for brain tumors the diagnostic sensitivity, specificity and accuracy of (18)F-FDG PET-CT was 53.3%, 72.7%, 58.5%, versus 96.7%, 90.9%, 95.1% of (11)C-MET PET-CT, respectively. All the primary foci in 9 patients with brain metastases were detected by body (18)F-FDG PET-CT scan. Semiquantitative analysis: There was a significant difference in the uptake between highly differentiated malignant and poorly differentiated tumors as well as non-neoplastic lesions for both tracers (P < 0.01), while between low-grade malignant tumors and non-neoplasm lesions, there was a difference in uptake only by (11)C-MET (P < 0.01). No significant difference between the uptakes in brain metastasis and glioblastomas was found by both tracers (P > 0.05). CONCLUSION: Both (18)F-FDG and (11)C-MET PET-CT are useful in differentiation of brain ringlike-enhanced lesions on MRI imaging. (11)C-MET PET-CT is more helpful than (18)F-FDG PET-CT in differential diagnosis of low-grade neoplastic from non-neoplastic lesions. Combination of (18)F-FDG and (11)C-MET PET-CT scans can improve the accuracy of differential diagnosis for brain ringlike-enhanced lesions on MRI imaging.